164 BROOKLYN BOTANIC GARDEN MEMOIRS 



the colony which show no capacity for reproduction and apparently 

 undergo senile degeneration. If, for example, as is so commonly 

 and loosely stated in textbooks, the colony were formed by marginal 

 growth and cell division, forming first a curved plate and finally a 

 sphere, so that the cells at one pole would be ontogenetically younger 

 than those at the other, we might expect this to be the basis for 

 differentiation of germ plasm and soma. The evidence is, however, 

 that all the cells of the adult colony are of the same generation and 

 ontogenetically equivalent. 



The difference in their behavior is to be sought, then, in their 

 relative environment and internal development as the colony grows. 

 Their position in the posterior portion as the colony swims and around 

 the pole which is nearest the point .of connection between daughter 

 colony and mother colony are obvious epigenetic factors in their 

 environment which may be of significance. The distribution of the 

 parthenogonidia at relatively equal intervals may be due to diffusion 

 phenomena affecting nutrition directly or as stimuli, the whole com- 

 plex perhaps suggesting analogy with Liesegang phenomena. 



The attempt to differentiate the eight daughter colonies commonly 

 formed in asexual colonies of V. glohator as descendants of the eight 

 cells produced by the third division seems to me wholly artificial. 

 This third division is not essentially difTerent from the other divisions. 

 In V. aureus also the number of daughter colonies varies. 



Meyer ('95) notes that the protoplasmic connecting strands 

 between the cells are more numerous in this region of the germ cells 

 than in the anterior part of the colony. They are especially well 

 developed between the germ cells and the sterile cells as Janet's 

 diagrams show so strikingly ('12, Fig. 4). It is also in this region, 

 as noted, that the young colony maintains its connection with the 

 mother colony through protoplasmic strands from the cells around 

 the posterior polar opening which connect with the adjacent cells of 

 the parent as shown by Overton ('89, Taf. Ill, Fig. 16), and Janet 

 ('12, Fig. i). The germ cells are borne then in that region of the 

 colony which up to birth was most directly connected with the mother 

 colony and perhaps received from it a large amount of food materials 

 in the early growth stages. 



The antheridia of V. globator form the so-called packets of anthero- 

 zoids consisting of bundles of sixteen to thirty-two gametes. These 

 are formed by binary fission of the mother cell in two planes. The 

 eight-cell stage shows the wheel figure. The cells instead of forming a 

 globular colony ordinarily form a flat plate like the simpler Gonium. 

 Whether this is really due to a tendency to recapitulation retained in 

 the sexual germ-cell formation or whether it is due to the elongation 



